Coffee-percolator.



H. G. JOHNSON. COFFEE PEROOLATOR. APPLICATION FILED JULY 25, 1907. nnnnwnn we. 19, 1910.

Patented Apr. 4, 1911.

2 SHEETS-SHEET 1.

w Illllll IN VENTOR A TTORNE Y H. G. JOHNSON.

COFFEE PERCOLATOR.

APPLICATION FILED JULY 25, 1907. RENEWED we. 19, 1010.

Patented Apr. 4, 1911.

2 SHEEN-SHEET 2.

UNITED STATES rag-Eur OFFICE.

HAROLD C. JOHNSON, OF CHICAGO, ILLINOIS.

oorrnn-PnRcoLAroR.

'1 988 470o Specification of 'Letters Patent.'

Application filed July 25,19 07,Seria1 No. 385,410. Renewed August 19, 1910. Serial No. 577,994.

' To all whom it may concern:

Be it known that I, HAROLD C. JorINsoN,

. 'acitizen of the United States, residing at Chicago, in the'county of Cook and State of 5 Illinois, have invented a certain new and useful Cofiee-Percolator, of which the following is a specification. a

My 'nvention is a vessel cdnstructed of pottery which can be placed upon the stove lo jnnd used to boil liquids in without danger of cracking the vessel.

Heretofore, when a vessel of pottery was placed upon the stove, the sudden expansion caused it to crack. 'I have discovered that if the sidewalls which come in contact with the stove are formed relatively thicker than the remaining portion of the vessel, and that if the bottom is formed much thinner than the side walls and preferably concave, that the thin bottom wall will act in the nature of a diaphragm, and, by reason of its flexibility adjust itself to the varying conditions resultant from the unequal expansion caused by the heat. My invention is primarily designed to construct 'a vessel which may be used in combination with 'c'ofi'ee percolatin apparatus, and which will, when so use percolate in less time than any metal pot, and will continue to percolate for a considerable period of timeafter removal from the stove. It hasfor its further object to provide a vessel for distilling those chemicals which, by reason of their inherent qualities, will corrode any but the most expensive metals, such as gold, platinum, etc., as the glazed pottery affords an ideal surface for such work and will stand the heat much better than glass. I

My means of attainin the foregoing ob- 'jects may be more readily understood by having reference to the accompanying drawings, which are hereunto annexed and are a part of this specification, in which,

Figure 1 is a side elevation of a vessel constructed in accordance with my invention, having a part of the side broken away to show the interior. Fig. 2 shows a modi-,

fied form of construction.

Similar reference numerals refer to similar parts throughout the entire description. For the purpose of showing the, invention reduced to concrete form, I have illustrated a coffee percolating apparatus, but it will be apparent that my invention may be used in a number of shapes andefor difl'erent purposes, all of which fall properly within the scope of my invention. y

'In the drawings, the vessel is shown as a coffee pot the body being indicated by'the numeral 1. This body isprovided with,,a

being formed of pottery which is vitrified and then glazed, and the bottom of whichis provided with a recess 4 which. is; surrounded by a wall 5. This wall is shown as formed considerably thicker than the remaining part of the wall of the'body 1. This thickened portion extends around the bottom 7 of the body 1. The bottom '7 may be slightly concave to provide an air chamber between the lid of the stove and the exterior face of the bottom wall so that only into. actual contact with the stove.

It is a recognized law of physics that the fluid at the bottom of a receptacle, which fluid is being boiled,.is but one degree, or a slight portion of a degree, higher. than the boiling point. Obviously, if it were greater, the fluid wouldlmrst into steam. It results from this law that by making the bottom wall 7 concave so as to keep it fronrdirect is a very few degrees, if any, higher than the boiling point; wh1le, constructing it thus lower itself, its position being determined by the degree of heat to which the sidewall 5 has been raised and the degree which it has correspondingly expanded, which will be more or less according to the intensity of the heat to'which it is subjected, while, by reason of the thinness of the bottom wall 7, it affords ready and easy transmission of the heat units from the stove to the liquid in the interior of the vessel while the thickened wall 5, which comes in contact with the stove, is of sufficient mass to resist the action of the heat, even though constructed of a fine grade of pottery.

Nithin the recess 4, in the interior of the vided with flanges 9 and a rim 10, the latter being'adapted to extend over the edges of the recess 4. Another difficulty which pre-. sents itself to the constructionof a vessel for this use of pottery has been due to the fact that the recesses are uneven in size and,

- Patented Apr. 4, 191 1.v

the lower portion of the wall 5 is brought body 1, I locate a member 8, which is pro suitable handle 2 and a spout 3, the bodv "1 A A i an ogee shape, though it is obvious it may be straight if desired. The'lower portion 6 is i contact with the stove, the temperature of it permits the bottom wall 7 to either raise or as a consequence, the member 8, which is preferably formed of metal, could not be constructed so as to satisfactorily operatebecause of the extreme variation in the size of the recess 4:. It will be apparent that I avoid this difficulty by reason of theextension of the rim 1.0, it contacting with the inner wall of the body beyond the edge of the recess, so that if the rim 10 is constructed of sufficient size, it does not matter if thecup-sha'ped member is considerably smaller than the recess, thus permitting it to be used in all of the different pots.

A tube 11 is secured to themember 8; the upper portion of the tube being formed into a basket 12, the side and bottom of which maybe perforated, and which is adapted to hold the coffee or whatever article is to be distilled, the tube and receptacle being formed -integral.

For some uses it may be founddesirable to construct the pot as shown in the modified"'fo1'1n illustrated in Fig. 2 of the drawfound cheaper in practice to manufacture,-

ingsfwhere it is desired to percolate a larger amount of coffee, and whereit is-desirable to retain the heat in the walls of the vessel for a longer period of time. In this form, the bottom is constructed with a'recess '13,

the side walls '14: of which are uniform in thickness, the bottom 15 may be if desired relatively thinner than the side walls and is constructed so as to come in contact wit-hthe lid of the stove. This construction may be while the difference in t-hicknesspermits the bottom to adjust itself to the expansion of the side walls, it being obvious that the larger mass of pottery will take a longer time to 0001 after the vessel is removed from then placed upon the vessel and it is set upon the lid of the stove. The heat, passingthrough the thin bottom wall ,7,- boils the water in the recess 4, causing it to. pass up the interior of the tube 11, from the top of which it escapes, falling into the basket,

where it comes in contact with the coffee. It

drops through the perforated sides, drawing the extract from the coffee, thus. within a very short time transforming the water into drip coflee, which is free from grounds, it

being obvious that'they will be retainedby the basket 12.

Having described my invention, what I re ard as new, and desire to secureby Letters Patent, is:

1. In a device of the character described,

the combination with a vessel made of pottery having a recess in the lower portionthereof, the side walls of the said recess being relatively thicker than the remaining walls of the body portion,.said recess walls being joined by a bottom wall relatively thinner than the side walls, percolating apparatus located within the said recess, said apparatus being provided with a flange and a rinnthe said rim extending over and be-- yond the edges of the recess.

2. In a device of the character'described, thecombination with a vessel made of pottery having arecess in-the lower portion thereof, the side walls of the saidrecess-be ing'relatively thicker than the remaining walls of the body portion, said recess walls being joined by a concavebottom wall relatively thinnerflthanth-e side walls,-percolating apparatus located within the said recess,

said apparatus being provided with a flange and a rim, the said rim extending over and beyond the edges of the recess.

HAROLD O. JOHNSON. Witnesses:

A. NELSON,

H. L. Donson. 

